Harry Potter is a fictional orphan locked in a cupboard by his aunt and uncle, after which he discovers a magical world and a better class of nemesis than his ugly suburban relatives. It seethes with class. The Dursleys are lower-middle-class, golf-club-haunting gammons. I suspect their MP is Dominic Raab, and I suspect they vote for him. The improved nemesis ‘Lord’ Voldemort is half landed gentry and heir to a Jacobean manor house on a hill.

Harry Potter is world famous, and so people want to join him in suburban misery (we are near Watford), though in a slightly larger cupboard: the vast prop room in a former sound stage off the M1 called the Warner Bros Studio Tour London — the Making of Harry Potter. Harry is a boiler-plated mythical hero. His ordinariness is absolute. His loneliness, like that of Frodo Baggins, keens at you. Like all effective mythical worlds this one is never-ending; but imagination does have limits. The food is not very good. It is not quite the nadir of the Legoland Windsor Resort, which was named ‘deep-fried-crap land’ by the Soil Association. (The insinuation was: eat the Lego.) But lightning, as Potter knows better than anyone, doesn’t strike twice.

Here be dragons beyond car parks. I like the Wizarding World of Harry Potter because it is set in a posh school — who is immune to dreams of class? — and it is a world beneath a world. This is conspiracism, but benevolent and hopeful conspiracism, and that is rare these days.

We pass the interior sets: the great hall based on Christ Church, Oxford, the goblin bank, the alley of shoppes, which also comes in Lego (in case Watford, or your own mind, is too far to travel). They are perfect, and ruinous. No dreamworld should be prodded too closely: detail destroys their power. I am grateful I went to Lavenham the day before to see De Vere House, which was part of Godric’s Hollow in the films. We were not admitted — it is an overpriced B&B in the real world — and it kept its mystery with that.

Beyond the hall is the Backlot Café, decorated as a branch of Ikea: a metal roof; vast windows; pipes. This feels like theft in a place containing the greatest production design cinema is capable of, but perhaps it is a homage to Harry’s hungry childhood. Or perhaps it is mere laziness.

This is not the first Potter-themed restaurant I have visited: I had a full English breakfast in a fake Three Broomsticks in a fake Hogsmeade village in Orlando ten years ago. It was not perfect — over-salted and wet — but it felt ambitious. The Backlot Café has no such ambition: it has all been drained away. It offers a dispiriting menu of burgers, hot dogs and fries. (Soup here is an outlier. Its presence feels brave.) There is, though, Butterbeer: an attempt to bring a fictional drink to life. It is OK, if you like the taste of sugar. It is like drinking orange candyfloss.

I have an adequate chicken burger. He has a packed lunch served inside a cardboard box printed to look like the Knight Bus (a magical Routemaster). The most interesting thing was the cardboard; the diners are closer to hostages.

It’s not a destination restaurant for fried chicken burgers but I am, at last, certain of one thing that has always bothered me; or almost certain. Looking at the breadth of this world — café aside — I think it is flimsier than I imagined, even for him. That is: I don’t think Harry ever made it out of the cupboard.